Extension I

By use of an extension I spell the magic-user prolongs the duration of a previously cast first, second, or third level spell by 50%. 

Thus, a levitation spell can be made to function 1-½ turns/level, a hold person spell made to work for 3 rounds/level, etc. Naturally, the spell has effect only on such spells where duration is meaningful.

This spell must be cast after the spell to be extended, whether by another spell-user during the same round, or the initial spell caster or another immediately preceding the casting of the extension. If a round elapses, the extension goes for naught.